In the field of communications technologies, with the development of emerging applications, wireless access networks are developing toward high-capacity, millimeter-wave, and multiple-band applications. Therefore, wireless devices impose a higher requirement on antennas. To adapt to this requirement, an antenna needs to be in a low-profile form to meet a requirement of millimeter-wave band wireless device integration, and also needs to have a high gain feature to adapt to a scenario of high attenuation during millimeter-wave band signal propagation.
Because a feeding unit and a radiation unit of a leaky wave antenna (LWA) are simple in structure, and the leaky wave antenna is suitable for a planar structure and has a wideband feature, the leaky wave antenna has become a main technical solution used in design of a low-cost, low-profile, and wideband antenna.
A radiation principle of the leaky wave antenna is: A signal wave formed by means of excitation inside the leaky wave antenna by a feeding unit is radiated in a form of a leaky wave and along an aperture formed by the leaky wave antenna, to implement signal transmission.
However, when a leaky wave antenna in the prior art transmits a millimeter-wave band signal, because the signal is transmitted along an aperture of the leaky wave antenna at the same time when a leaky wave is radiated, a signal amplitude of the leaky wave antenna is attenuated exponentially in a surrounding direction from the feeding unit, on an aperture plane, of the leaky wave antenna, causing relatively low aperture efficiency of the antenna and a relatively low gain of the antenna.